block paving...

[Tim Lamb]

Rather than high jack the other thread I thought I would start my own:-)

Currently on the 5th. bag of sharp sand so you can guess my finger tips would be wasted at a crime scene. On advice in here, I skimmed the McCormack site and found it very helpful.

Couple of points arising... scaffold poles make excellent guides for laying out the sharp sand after wacking the hard-core: use a third pole to level off.

Also... build the retaining walls last! No amount of careful measurement will avoid endless block cutting:-(

regards

[Phil L]

I wouldn't use a pole to trammel with, you need something with a square edge, a round pole will ride over lumps and bumps but a board will scrape the tops off, you've a chance of partially compacting areas with a pole, these won't go down as far as surrounding areas when whacked and you'll be left with bumps here and there

This an issue I have with McCormack's site, he always states that edgings should be concreted in prior to laying the body of the drive...in an ideal world this would be great, but surely it's more sensible to put all full blocks in, then the edgings in last, rather than work to a specific boundary and have a million fragments of block around the edges, which in my opinion, looks like a badly put together jigsaw puzzle

[Nightjar]

Phil L wrote: ...

I had a lot of blockwork laid whn I moved into this house, both straight and curved. The contractors did exactly what McCormack recommends and the only blocks they cut were half blocks that were an unavoidable part of the pattern reaching the edge. Presumably that is the difference betweeen professionals doing it regularly and amateurs doing it perhaps once in a lifetime.

Colin Bignell

[Tim Lamb]

Umm... does seem to work though:-)

I guess it makes for generous use of sand which may temper slight inequalities. Not allowing the scraper pole to *roll* requires a bit of effort. The technique adopted was to shovel moist sand up to the scraper and only attempt levelling 18" or so at a time. This avoids knees and feet causing local compaction.

I started off using T section suspended ceiling steel but found this difficult to remove without wrecking the beach:-) Poles pull out very easily and the slots left can easily be filled.

Yes. I am considering how to match the colour and aggregate used for my second hand concrete blocks where I have created a wedge 5m long going from 0 to 50mm. Had I simply prepared a suitably wide foundation the edge blocks could have been secured later:-(

regards

>

[Tim Lamb]

Umm.. Some of my problems were unavoidable: where existing structures were not 90 deg. or exactly parallel to the start point. Much head scratching preceded laying the first block but the edge to a herbaceous border could easily have moved a bit. *Growing* the bond could overcome small gaps but with uniform-ish colour (apart from the chewing gum splodges) blocks the only interest found by the eye is the linearity of laying.

regards

[Phil L]

Nightjar

[Nightjar]

[Phil L]

As I said earlier, it's impossible, how, with a curved edge are they able to use only full blocks and halves? - any photos?

That wasn't what you said, you said half blocks....if the edgings were already concreted in and even if they started at the edge you are thinking of with full and halves, they must have had pieces along the opposite edge, or as I said, further back into the body of the paving.

It makes not one iota of difference to the finished product anyway, it's just easier to use larger pieces than be left with lots of smaller pieces, for instance, if I am working to a concrete fence at one side and a wall at the other, I will stop the paving at the last full / half that I can fit in, and if this leaves a 50mm gap along wall or fence, it gets pointed with coloured concrete, rather than take the blocks right up to the boundary and have a million slithers of blocks on display

[John Rumm]

If you read on, he also cautions against using fragments, and advocates altering the pattern at the edge to use half or larger block pieces to remove the need for small bits. I have tried this myself, and it looked fine.

[Phil L]

It does look fine and I have also done it, but it's easier still if you aren't working to a pre-defined boundary

[John Rumm]

Yup sure...

As long as you have a decent depth of concrete haunch in place you mortar your edge course onto there is nothing wrong with adding the edge course after.

Personally I quite like having it there for curvy or other more complex layouts in advance since it give you a nice level to screed from.

[Nightjar]

No cuts of any sort were needed for the curve. It was a large arc of a circle with the blocks laid radially. The radius is large enough (3m internal diameter IIRC) that the taper in the joints is not obvious.

Correct. Cutting blocks in half was what was needed where the pattern met the edge. The rectangular areas were laid herringbone, with the blocks laid parallel to the edges.

and, as I said, I watched and they did not.

Most of the hard surfacing I had laid was laid without restrictions at the edges, although a few bits had an existing wall along one edge. The rest was laid to lawn or flower beds.

Colin Bignell

[Tim Lamb]

In message , John Rumm writes

OK. So back to the useful bit.. how do you match infill to the blocks?

Mine appear to be made from a 6mm or so aggregate with the top possibly acid etched to expose the stone.

regards

>

[John Rumm]

Normally by cutting a notch out of the ends of my screeding bar:

_________________ |__ __| |___________|

The ends ride over the prepared edges, and the bottom scrapes the compacted sand to the required level. When using "normal" 50mm high blocks one can also place a 4x2 on its side laying on the sand to form another screeding rail should it be required.

If too lumpy to screed from directly, then a thin wood rail can be laid over the top and deeper notches cut in the screeding board.

[Tim Lamb]

Sorry, question not set out well.

Hiding head in shame, I am proposing to mix a sharp sand, suitable aggregate and cement to try and match the visual appearance of the laid blocks where I have silly (up to 35mm) gaps.

regards

>

[Phil L]

My advice is to take up paving with any gaps larger that a few mm and relay, anything else is going to look revolting now and in the future

[John Rumm]

Not convinced that's ever going to look nice! Can't you relay a few to eliminate the gaps (even if it means that you consolidate the gaps into one larger one at an edge that you can fill with a mortar screed)

[Tim Lamb]

er.. they are already at the edge. That is the problem caused by building the walls first:-)

I have been very careful to maintain the intervals between the blocks, despite having some with spacer nibs and some without. Smarting slightly from the *amateur* appellation bestowed by Phil L, I have made up some steel spacers as temporary guides.

Cutting 75x200x100mm concrete blocks is a non trivial activity particularly as they are too deep to easily cut with a 230mm blade.

regards

>

[John Rumm]

Ah , ok I see what you mean...

So you either need to knock the edge course loose and relay it snug or cut blocks to fit.

Easy if you hire a decent block snapping machine. Failing that just to a partial cut with a diamond blade and clomp em . No need to go all the way through, they will break at a partial cut. (cut at a slight angle from the top, so any roughness at the broken edge is away from the adjacent block).